EFFECT OF AZELASTINE ON SULFUR-DIOXIDE INDUCED IMPAIRMENT OF CILIARY MOTILITY IN AIRWAY EPITHELIUM

Objective-The effect of azelastine on airway mucociliary transport fun ction was studied by measuring ciliary motility of human bronchial epi thelium in vitro with a photoelectric method. Method-Bronchial epithel ial cells were obtained by fibreoptic bronchoscopy, mounted in a Rose chamber, and perfused with Krebs-Henseleit solution. The preparations were placed on a microscope stage equipped with an illuminator, and th e variations of light intensity caused by ciliary beating were detecte d by a photometer. Results-The addition of azelastine to the perfusate increased ciliary beat frequency (CBF) in a dose dependent manner wit hout ciliary discoordination. The mean (SE) maximal increase from the baseline value and the concentration required to produce a half maxima l effect were 27.0 (4-2)% and 9.2 x 10(-6) mol/l, respectively. Exposu re of the cells to the perfusate containing 3 ppm sulphur dioxide rapi dly decreased CBF by 59.2 (5.0)%, and was accompanied by a reduction i n intracellular cyclic AMP levels from 38.1 (4.3) to 10.1 (2.4) pmol/m g protein. This effect was prevented by pretreatment of cells with aze lastine in a dose dependent manner. Conclusions-Azelastine not only st imulates ciliary motility of airway epithelium and hence mucociliary t ransport function, but may also protect against sulphur dioxide induce d ciliary dysfunction, probably by inhibiting intracellular cyclic AMP loss.